Finishing mill for thin sheet metal



April 1, 1958 K. F. UNGERER 2,828,654

FINISHING MILL FOR THIN SHEET METAL Filed sept. 15. 1953 By.' Y

.ipe

nite-i itates @arent FINISHING MEL FOR THEN SHEET METAL Karl Fritz ling-eter, Pforzheim, Germany Application September TLS, 1953, Serial No. 380,258

Claims priority, application Gennany November 2S, 1952 6 Claimsa (Cl. titl-38) The present invention relates to a finishing mill for thin sheet metal, and is particularly directed to an improved finishing mill of this kind provided with at least one bendable finishing roll.

in order to make thin sheet metal suited for deep drawing, annealing of the sheet metal is necessary. But annealed sheet metal easily yields to buckling and bending, and to remove bends or flaws produced for instance during the straightening, during the transport, or during the unwinding from the coil, is almost impossible. Flaws of this kind will remain visible even on deep drawn and lacquer coated sheet metal. This lack of resistance of annealed s ieet metal to buckling and bending prevents for annealed sheet metal the use of economie` working and transportation methods, or at least renders the use of such economic methods very diicult.

To improve for thin sheet metal, which has been adapted for deep drawing, the capacity of resistance to buckling and bending by means of a finishing treatment, is already known to the art. With the aid of this finishing treatment the sheet metal has its surface hardened through cold compression or surface deformation by means of slight rolling. This surface hardening reduces to some extent the suitableness of the sheet metal for deep drawing, but increases considerably its capacity of resistance to buckling and bending. The finishing mill used for the surface hardening consists of either a pair of rolls of considerable diameter, or of a pair of rolls of smaller diameter, which however, in order to prevent bending of the rolls, have to be supported during their rotation on both sides by a plurality of supporting rolls, or by a row of separate, shiftable supporting members.

Both of these known types of finishing mills have the drawback that, whenever the sheet metal is of non-uniform thickness as frequently happens in the production of sheet metal, the thicker sheet metal portions are subjected to considerably more cold deformation than the thinner portions, so that the Capacity of resistance of the thinner portions to buckling and bending frequently remains unsatisfactory.V ln addition to this, these known finishing machines are so expensive that the producers and subsequent consumers of the sheet metal are not always in a position to make use of them.

The aforesaid disadvantages of known constructions are avoided by the machine of the present invention. According to the invention the finishing machine is provided with at least one bendable finishing roll which in the direction of the rolling pressure is elastically supported in working position by a plurality of shiftable supporting members, whereby the construction is so devised that the plurality of shiftable supporting members are interconnected in such a way that the exerted pressure is uniformly distributed among the plurality of shiftable supporting members. The cross-section of the gap between the finishing rolls does then automatically adjust itself to the varying cross-section of the moving sheet metal. If the diameter of the finishing rolls is small enough, the finishing rolls are thereby enabled to bend in conformity with the unevennesses of the sheet metal. The varying pressure exerted against the bendable and elastically supported finishing roll is distributed among the plurality of shiftable supporting members in such a way that pressure exerted against one portion of the bendable and elastically supported finishing roll results in bending of that portion and in temporary yielding of the shiftable supporting member of that portion to the bending pressure, but simultaneously causes the associated shiftable supporting members to counteract the pressure by increasing their supporting pressure through oppositely directed supporting movements.

ln a preferred embodiment of the invention only one finishing roll, viz. the lower one, is elastically supported by interconnected shiftable supporting members, while the upper finishing roll is rigidly supported by non-yielding and not interconnected supporting members.

Summing up it can be said that known finishing machines differ from the finishing machine of the invention essentially in the feature that in known finishing machines the cross-section of the gap between the finishing rolls remains unchanged and that therefore the pressure exerted by the finishing rolls upon the cross-section of the sheet metal is caused by and depends upon the degree of unevenness of the surface of the sheet metal, while in the finishing machine of the invention the crosssection of the gap between the finishing rolls constantly changes in conformity with the irregularities of the crosssection of the sheet metal, and that the pressure exerted by the finishing rolls upon the sheet metal remains a uniform one throughout the entire cross-section of the sheet metal.

The result is that in the finishing machine of the invention the sheet metal is uniformly cold deformed and uniformly hardened at every portion of its surface, regardless of unevennesses of the surface.

In addition to this, the finishing machine of the invention is of a comparatively small size andlow price, so that it can be employed by producers and consumers of sheet metal everywhere where its use appears to be advisable for the prevention of bends and flaws in the sheet metal.

The invention further proposes to devise the construction in such a way that the shiftable supporting members of the elastically supported finishing roll are mounted on a plurality of hydraulic pistons plunging into the same hydraulic vessel, while the shiftable supporting members consist of rolls Vof small diameter which are supported in ball bearings or roller bearings, and which bear against the finishing roll to be supported.

The shiftable supporting rolls are preferably arranged in two groups or rows in such a way that the supporting rolls of one row are staggeredly positioned with respect to, and engage in the gaps between, the supporting rolls of the other row.

Additional features and advantages of the invention will oe understood from a consideration of the following detailed description taken in connection with the accompartying drawings, forming a part of this specification, and in which a preferred embodiment of the invention has been shown by way of illustration. However, I wish to say that the invention is not confined to any strict conformity with the showing of the drawings, but may be changed or modified, so long as such changes or modifications mark no material departure from the salient features of the invention as expressed in the appended claims.

in the drawings:

Fig. l is a longitudinal section of a pair of finishing rolls of known construction, showing how the finishing rolls merely act upon the bulging portions ofthe sheet metal;

Fig. 2 is a longitudinal section of the finishing machine of the invention, showing how the iinishing rolls uniformly bear against the entire surface of the sheet metal;

Fig. 3 is a Vcross-section of the finishing machine of Fig. 2, showing two pairs of iinishing rolls arranged behind each other, and three rows of supporting rolls for the support of the iinishing rolls.

Referring now to the drawings in detail, the reference numerals and 3 denote the rolls of the known finishing machine illustrated in Fig. l. AThe rolls 2 and 3 are of considerable cross-section and journaled at 4, 5 and 6, 7 in the framework of the mill (not shown in the drawings). The sheet metal 8 is (in the embodiment of Fig. l) of bulging cross-section in the center, and subjected tocold deformation and hardening only at the bulging places, while the surface portions positioned near the lateral edges are not acted upon by the rolls, and for that reason are not rendered capable of resisting buckling and bending. The gap between the two rolls (indicated by the dot-and-dash lines) is of uniformly rectangular shape.

In the rolling mill illustrated in Fig. 2 the lower finishing or working roll 9 adjusts itself to, and snugly bears against, the bulging surface of the sheet metal 10, so that the cold deformation is a uniform one throughout the entire cross-section of the sheet metal, while the shape of the gap between the rolls constantly varies in conformity with the cross-section of the sheet metal. The finishing roll 9 and its counter roll l1 are journaled at l2, 13 and 14, 15 in the framework of the mill (not shown in the drawings), and driven by means of cardan shafts 16, 17 from the driving means i3. Both of the rolls 9 and 1l are thin enough to permit bending. For the roll 11 bending is, however, prevented. The supporting means or pressure members consist, as shown in Fig. 3, of three rows of supporting or pressure rolls 19, 20, 30 and 21, 22, 31, which are staggeredly arranged in such a way that the rolls of the center row engage in the gaps between the rolls of the adjacent rows. The groups of the upper supporting rolls 19, 2i), 3d are rigidly supported in the block 23, while'kthe lower groups of supporting rolls 21, Z2, 31 are mounted on the pistons 24, 25, 32 which plunge into three different hydraulic tanks 26, 27, 33. in each of these tanks the hydraulic pressure is produced in known manner by means of the pumps 2S, 29, 34. The pressure can be changed according to requirements. As all of the pistons of one group of pistons plunge into the same hydraulic vessel, every increased or reduced pressure caused at one supporting roll 21, 22, 3l through unevennesses of the sheet metal is evenly distributed among all of the supporting rolls of the same group of rolls, so that the nishing roll is always under uniform supporting pressure throughout its entire length. Of course, it is also possible to devise the construction in such a way that the rigidly supported nishing roll is arranged below, and that the hydraulically supported finishing roll is positioned above, or that both of the iinishing rolls are hydraulically supported. As, however, hydraulic installations are rarely of perfectly tightly closed construction, the arrangement of Fig. 2 has the advantage that it facilitates the collection of escaped oil and thus prevents the oil from passing onto other parts.

Of the two pairs of iinishing rolls 9, il and 35, 36 the first pair of rolls 9, ll should preferably effect only a portion of the surface deformation of the sheet metal. For the support of the two pairs of finishing rolls, three rows of staggeredly arranged supporting rolls are enough, as the supporting rolls 30 and 3i of the central row are so positioned that they simultaneously support bothof the iinishing rolls ii, 36 or 9, 35, respectively. In this liti way it is possible to reduce the number of rows of supporting rolls above and below to only three, as compared with the four rows of supporting rolls needed above and below when two machines are arranged behind each other. On the other hand, the separate arrangement behind each other of two machines has the advantage that the speed of each pair of finishing rolls can be accurately adjusted to the running speed of the sheet metal.

What l claim as new and desire to secure by Letters iatent of the United States is:

l. In a rolling mill, in combination, a framework; two pairs of rolls arranged in sequence in the direction of travel of a metal sheet to be rolled therein, said rolls being rotatably journalled on said framework and the rolls of each of said pairs of rolls being substantially parallel to and spaced from each other so as to permit rolling of a metal sheet between them, at least one of the rolls of each pair of rolls being bendable; and yieldable pressure means comprising a plurality of rollers arranged in first, second and third rows parallel to said two bendable rolls, said second row being located between said first and third rows, said iirst and second rows yieldably engaging one of said bendable rolls and said second and third rows yieldably engaging the other of said bendable rows.

2. ln a rolling mill, in combination, a framework; at least one pair of substantially parallel rolls rotatably journaled on said framework, said rolls being spaced from each other so as to permit rolling of a metal sheet between them and at least one of said rolls being bendable; a plurality of pressure members spaced apart from each other longitudinally of said bendable roll and arranged in a row parallel to said one bendable roll and engaging the same at the side thereof distant from the other of said rolls; a plurality of means each individual to each pressure member for mounting the pressure members for individual movement transversely of said one bendable roll; and means providing a single pressure source connected to and acting individually on said pressure members to create the transverse movement thereof at the same pressure and receiving the reaction of any pressure members to modify the pressure of said single pressure source, so that each pressure member will apply equal pressure to said bendable roll, whereby the pressure exerted by said pair of rolls on a metal sheet of uneven thickness during rolling of the same will be equalized on every portion on the surface of said metal sheet and the distance of adjacent portions of said two rolls from each other during rolling of said metal sheet will vary in accordance with the variance in the thickness of portions of said metal sheet being rolled between said adjacent portions of said two rolls.

3. in a rolling mill, in combination, a framework; at least one pair of substantially parallel working rolls rotatably journaled on said framework, said working rolls being spaced from each other so as to permit rolling of a metal sheet between them and at least one of said working rolls being bendable; a plurality of pressure rolls spaced apart from each other longitudinally of said bendable working roll and arranged in a row parallel to said one bendable working roll and engaging the same at the side thereof distant from the other of said working rolls; a plurality of means each individual to each pressure roll for mounting the pressure rolls for individual movement transversely of said one bendable working roll; and means providing a single pressure source connected to and acting individually on sa'id pressure rolls to create the transverse movement thereof at the same pressure and receiving the reaction or" any pressure rolls to modify the pressure of said single pressure source, so that each pressure roll will apply equal pressure to said bendable working roll, whereby the pressure exerted by said pair of working rolls on a metal sheet of uneven thickness during rolling of the same will be equalized on every portion on the surface of said metal sheet and the distance of adjacent portions of said two working rolls from each other during rolling of said metal sheet will vary in accordance with the variance in the thickness of portions of said metal sheet being rolled between said adjacent portions of said two working rolls.

4. In a rolling mill, in combination, a framework; two pairs of working rolls arranged spaced from each other in the direction of travel of a metal sheet to be rolled between said two pairs of working rolls, said working rolls being rotatably journaled on said framework and the rolls of each of said pairs of working rolls being substantially parallel to and spaced from each other so as to permit rolling of a metal sheet between them, at least one of the rolls of each pair of working rolls being bendable; a plurality of pressure rolls respectively arranged ink first, second `and third rows parallel to said two bendable working rolls, said second row of pressure rolls being located between said first and third rows, said first and second rows of pressure rolls engaging the bendable working roll of one of said two pairs of working rolls at the side thereof distant from the other working roll in said pair, and said second and third rows of pressure rolls engaging the bendable working roll of the other pair of working rolls at the side thereof distant from the other working roll in said other pair; a plurality of means each individual to each of said pressure rolls for mounting the pressure rolls for individual movement transversely of the bendable roll respectively engaged by the same; and means providing a single pressure source for each of said three rows of pressure rolls respectively connected to and acting individually on said pressure rolls in each of Vsaid rows to create a transverse movement of the prese sure rolls in each row at the same pressure and receiving the reaction of any pressure roll in each row to modify the pressure of the Single pressure source respectively connected to said row, `so that each pressure roll in the respective row will apply equal pressure to said bendable working roll the respective row of pressure rolls is engaging, whereby the pressure exerted by said two pairs of working rolls on a metal sheet of uneven thickness during rolling of the same will be equalized on every portion on the surface of said metal sheet and the distance of adjacent portions of the working rolls in each of said two pairs of working rolls from each other during rolling of said metal sheet will vary in accordance with the variance in the thickness of portions of said metal lsheet being rolled between said adjacent portions of said working rolls.

5. In a rolling mill, in combination, a framework; two pairs of working rolls arranged spaced from each other in the direction of travel of a metal sheet to be rolled between said two pairs of working rolls, said working rolls being rotatably journaled on said framework and the. rolls of each of said pairs of working rolls being -substantially parallel to and spaced from each other so as to permit rolling of a metal sheet between them, at least one of the rolls of each pair of working rolls being bendable; a plurality of pressure rolls respectively arranged in first, second `and third rows parallel to said two bendable working rolls, said second row of pressure rolls being located between said first and third rows, said first and second rows of pressure rolls engaging the bendable working roll of one of said two pairs of working rolls at the side thereof distant from the other working roll in said pair, and said second and third rows of pressure rolls engaging the bendable working roll of the other pair of working rolls at the side thereof distant from the other working roll in said other pair, the pressure rolls in each row being spaced from each other in longitudinal direction of said bendable working rolls; a plurality of means each individual to each of said pressure rolls for mounting the pressure rolls for individual movement transversely of the bendable roll respectively Iengaged by the same; and means providing a single pressure source for each of said three rows of pressure rolls respectively connected to and acting individually on said pressure rolls in each of said rows to create a transverse movement of the pressure rolls in each row at the same pressure and receiving the recation of any pressure roll in eac'h row to modify the pressure of the single pressure source respectively connected to said row, so that each pressure roll in the respective row will apply equal pressure to said bendable working roll the respective row of pressure rolls is engaging, whereby the pressure exerted by said two pairs of working rolls on a metal sheet of uneven thickness during rolling of the same will be equalized on every lportion on the surface of said metal sheet and the distance of adjacent portions of the working rolls in each of Isaid two pairs of working rolls from each other during rolling of said metal sheet will vary in accordance with the variance in the thickness of portions of said metal sheet being rolled between said adjacent portions of said working rolls.

6. In a rolling mill, in combination, a framework; two pairs of working rolls arranged spaced from each other in the direction of travel of a metal sheet to be rolled between said two pairs of working rolls, said working rolls being rotatably journaled on said framework and the rolls of each of said pairs of working rolls being substantially parallel to and spaced from each other so as to permit rolling of a metal sheet between them, at least one of the rolls of each pair of working rolls being bendable; a plurality of pressure rolls respectivelyV arranged in rst, second and third rows parallel to said two bendable working rolls7 said second row of pressure rolls being located between said first and third rows, said lirst and second rows of pressure rolls engaging the bendable working roll of one of said two pairs of working rolls at the side thereof distant from the other working roll in said pair, and said second and third rows of pressure rolls engaging the bendable working roll of the other pair of working rolls at the side thereof distant from the other working roll in said other pair, the pressure rolls in each row being equally spaced from each other in longitudinal direction of said bendable working rolls and the pressure rolls in said second row are staggered with respect to said pressure rolls in said first and second rows; a plurality of means each individual to each of said pressure rolls for mounting the pressure rolls for individual movement transversely of the bendable roil respectively engaged by the same; and means providing a single pressure source for each of said three rows of pressurerolls respectively connected to and acting individually on said pressure rolls in each of said rows to create a transverse movement of the pressure rolls in each row at the same pressure and receiving the reaction of any pressure roll in each row to modify the pressure of the single pressure source respectively connected to said row, so that each pressure roll in the respective row will apply equal pressure to said bendable working roll the respective row of pressure rolls is engaging, whereby the pressure exerted by said two pairs of working rolls on a metal sheet of uneven thickness during rolling of the same will be equalzed on every portion on the surface of said metal sheet and the distance of adjacent portions of the working rolls in each of said two pairs of working rolls from each other during rolling of said metal sheet will vary in accordance with the variance in the thickness of portions of said metal sheet being rolled between said adjacent portions of said working rolls.

References Cited in the le of this patent UNITED STATES PATENTS 1,453,176 Perrins Mar. 18, 1921 1,614,424 Coe Ian. 11, 1927 1,824,211 Jobke Sept. 22, 1931 1,953,190 Paterson Dec. 21, 1931 2,611,150 Goulding Apr. 26, 1949 2,612,934 Dubosclard Oct. 7, 1952 2,677,978 Dahlstrom May 11, 1954 FOREIGN PATENTS 411,883 Germany June 6, 1924 

